#include <stdio.h>
#include <stdlib.h>
#include <math.h>

typedef int Elem;

typedef struct DoubleNode{
    Elem data;
    struct DoubleNode *lnext;
    struct DoubleNode *rnext;
} DNode , *DpNode;

int insert(DpNode L,Elem date)
{
 
    DpNode p = L;
    if(p==NULL)
    {
        return 0; 
    }
    else
    {
        while(p->rnext)
        {
            p = p -> rnext;
        }
        DpNode pnew=(DpNode)malloc(sizeof(DNode));

        pnew -> data = date;

        p -> rnext = pnew;

        pnew-> lnext =p;

        pnew -> rnext = NULL;  
    } 
} //尾插法向链表中添加元素

void init (DpNode *L)
{
    (*L) = (DpNode)malloc(sizeof(DNode));
    (*L)->rnext = NULL;
    (*L)->lnext = NULL;
}//初始化


int main ()
{   
    DpNode PI;
    DpNode N;
    init (&PI);
    init (&N);

    

    for (int i = 0 ; i < 600 ; i++)
    {
        insert(PI , 0);
        insert(N , 0);
    }

    int n;
    scanf ("%d" , &n);


    return 0;
}